FRIDAY, July 12 (HealthDay News) -- U.S. scientists who successfully transplanted insulin-producing islet cells from rats to mice say it is the first step toward animal-to-human transplant of islet cells for people with
type 1 diabetes.

The researchers at Northwestern Medicine in Illinois developed a method that prevented the mice from rejecting the rats' islet cells without the use of drugs to suppress their immune system.

The study was published online July 12 in the journal Diabetes.

"This is the first time that an interspecies transplant of islet cells has been achieved for an indefinite period of time without the use of immunosuppressive drugs. It's a big step forward," co-senior study author Stephen Miller, a research professor of microbiology and immunology at the Northwestern University Feinberg School of Medicine, said in a Northwestern news release.

Their ultimate goal is to be able to transplant pig islets into humans, said the other co-senior author, Dr. Xunrong Luo. "But we have to take baby steps," said Luo, medical director of the human islet cell transplantation program at Northwestern Memorial. "Pig islets produce insulin that controls blood sugar in humans."

People with type 1 diabetes don't produce insulin. A transplant of insulin-producing islets from a deceased donor can help control type 1 diabetes, but there is a severe shortage of islet cells from deceased donors. Many patients on waiting lists don't receive the transplant or suffer heart, nerve, eye and kidney damage while they wait.

Using islets from another species would enable more people to receive transplants. However, concerns about controlling rejection of transplants from a different species have made that approach seem impossible until now.